Height as a function of time word problem

Question

A reflector is fastened to the front wheel of a bicycle 20 cm from the center of the wheel. The diameter of the wheel and inflated tire is 70 cm. If the bike is traveling at 10 km/h, express the height of the reflector above the ground as a fuction of time. Assume that at time t = 0 seconds, the reflector is at its highest point.

Answer 1

Hint:-

Speed of bicycle wheel=${\frac {10^6}{3600}}$cm/s.

Circumference of wheel=$220\space cm$.

Now,calculate number of revolutions in $1 sec$ at the above given speed.

Now,express this as a function of time (in sec).